枝肉を汚染する微生物に関する研究 (IV)

Abstract

To examine the microbial contamination of dressed porcine carcasses induced by the scalding method conventionally used in the western part of Japan, viable bacterial counting was made and the isolated strains were classified. Counting was done on samples collected 0, 10, 30, 60, and 90minutes after scalding, and on samples harvested from the skin in the processes of scalding, dehairing, and washing. Results obtained are as follows.1) The viable aerobic bacterial count of the scalding water was (2-10)×102immediately before scalding, (11-23)×10310minutes after scalding, (12-32)×103at 30 and 60minutes, and (12-36)×103at 90minutes. The viable anaerobic bacterial count was 3×10immediately before scalding and increased gradually after scalding, reaching 97×10 at 90minutes.2) The viable aerobic bacterial count of the pig skin increased gradually in the process of dehairing. It was (16-30)×105immediately before washing of the dressed carcass and was maintained almost at this level after washing.3) Gram-positive rods were predominant among the isolated strains. Micrococcus was isolated 10-20 minutes after scalding. Achromobacter, Streptococcus, Leuconostoc, and Alcaligenes were isolated at a low rate.4) Predominant after scalding were Micrococcus. Escherichia coli, Leuconostoc, Gaffkya, Staphylococcus, Pseudomonas, Alcaligenes, Achromobacter were isolated at nearly the same rate as the Grampositive rods.5) Higher proteinase activity was shown by strains which contaminated the carcass probably after scalding than by the Gram-positive rods which were predominant in scalding water.